Ediacaran origin and Ediacaran-Cambrian diversification of Metazoa.

The timescale of animal diversification has been a focus of debate over how evolutionary history should be calibrated to geologic time. Molecular clock analyses have invariably estimated a Cryogenian or Tonian origin of animals while unequivocal animal fossils first occur in the Ediacaran. However, redating of key Ediacaran biotas and the discovery of several Ediacaran crown-Metazoa prompt recalibration of molecular clock analyses.

Historical record of heavy metals in the mollusk shells of the Nile Delta.

Identifying the baseline status and the timing of ecosystem disturbances are essential for restoration programs. The historical bioaccumulation of heavy metals was assessed from an 80-cm-long core from the Manzala Lagoon (Nile Delta). The heavy metal concentrations increased slightly upward and peaked around 1964, after the completion of Aswan High Dam.

 sp. nov. (Bacillariophyta) from the Shun River in Hunan Province, China.

A new species, , was found in the Shun River of Hunan Province, southern China, and its morphology was described based on light and scannning electron microscope obervations. is characterized by its lanceolate valve outline, apiculate valve apices, slightly undulate valve margins, mostly biseriate striae, variable central area, and closed valvocopula. Many abnormal valves of were observed in the samples investigated and the most frequent morphological abnormalities consisted of a lack of symmetry relative to the apical axis caused by a unilateral expansion in the middle part of the valve.

Unique Jurassic Ovaries Shed a New Light on the Nature of Carpels.

Enclosed ovules are a reproductive feature restricted to angiosperms. Although this feature can be used as a criterion for identifying fossil angiosperms, how ovules are enclosed and the nature of the placenta are still foci of debates. A reason underlying these controversies is the lack of reproductive organ fossils shedding light on these issues.

: A Fossil Link between Conifers and Angiosperms.

The flowering plants (angiosperms) are the dominant and defining group of the Earth ecosystems today. However, from which group and by what way flowers, especially their gynoecia (the key characteristic organs of angiosperms), are derived have been key questions in botany, and have remained unanswered despite botanists' efforts over centuries. Such an embarrassing situation can be attributed to the lack of plants with partially enclosed ovules, which are supposed fill a position between gymnosperms and angiosperms.

The Perizonium Ultrastructure, Divided Apical Pore Fields, Various Pore Occlusions and Visible Intermissio of (Bacillariophyceae) with Descriptions of Four New Species.

The initial valves of two species are observed under a scanning electron microscope, and the perizonium ultrastructure of is revealed for the first time. The perizonium is composed of alternate nodes and internodes and lacks transverse perizonium bands. Four new species, sp.

Flower Buds Confirmed in the Early Cretaceous of China.

The Yixian Formation (Lower Cretaceous) in China is famous worldwide for its fossils of early angiosperms, but there has been only one record of flower buds () hitherto, in which only the surface of the flower bud was documented while no internal details were known. Such a partial knowledge of flower buds hinders our understanding of the evolution of flowers, and this knowledge lacuna needs to be filled. Our new specimen was collected from an outcrop of the Yixian Formation (Barremian-Aptian, Lower Cretaceous) near Dawangzhangzi, Lingyuan, Liaoning, China.

Contrasting water-use strategies to climate warming in white birch and larch in a boreal permafrost region.

The effects of rising atmospheric CO2 concentrations (Ca) with climate warming on intrinsic water-use efficiency and radial growth in boreal forests are still poorly understood. We measured tree-ring cellulose δ13C, δ18O, and tree-ring width in Larix dahurica (larch) and Betula platyphylla (white birch), and analyzed their relationships with climate variables in a boreal permafrost region of northeast China over past 68 years covering a pre-warming period (1951-1984; base period) and a warm period (1985-2018; warm period). We found that white birch but not larch significantly increased their radial growth over the warm period.

Soil organic nitrogen variation shaped by diverse agroecosystems in a typical karst area: evidence from isotopic geochemistry.

Background: Soil organic nitrogen (SON) levels can respond effectively to crop metabolism and are directly related to soil productivity. However, simultaneous comparisons of SON dynamics using isotopic tracing in diverse agroecosystems are lacking, especially in karst areas with fragile ecology.

Methods: To better understand the response of SON dynamics to environmental changes under the coupling of natural and anthropogenic disturbances, SON contents and their stable N isotope (δN) compositions were determined in abandoned cropland (AC, = 16), grazing shrubland (GS, = 11), and secondary forest land (SF, = 20) from a typical karst area in southwest China.

Transformation of the pectoral girdle in pennaraptorans: critical steps in the formation of the modern avian shoulder joint.

Important transformations of the pectoral girdle are related to the appearance of flight capabilities in the Dinosauria. Previous studies on this topic focused mainly on paravians yet recent data suggests flight evolved in dinosaurs several times, including at least once among non-avialan paravians. Thus, to fully explore the evolution of flight-related avian shoulder girdle characteristics, it is necessary to compare morphology more broadly.

A new freshwater species of (Bacillariophyta) from Hunan Province, China.

This study describes a new species of , , on the basis of light and scanning electron microscope images. is characterised by its linear valve outline, extremely divergent striae, and very large hexagonal central area occupying ca. 1/5-1/8 of the valve length.

Cultivation and morphology of jujube (Ziziphus Jujuba Mill.) in the Qi River Basin of Northern China during the Neolithic Period.

This transition from gathering to cultivation is a significant aspect of studying early agricultural practices. Fruit trees are an essential component of food resources and have played a vital role in both ancient and modern agricultural production systems. The jujube (Ziziphus jujuba Mill.

Origin of Angiosperms: Problems, Challenges, and Solutions.

Angiosperms are frequently assumed to constitute a monophyletic group. Therefore, the origin of angiosperms is a key question in systematic botany since the answer to this question is hinged with many questions concerned with angiosperm evolution. Previously, the lack of fossil evidence undermines the robustness of related hypotheses, and explains the instability of the systematics of angiosperms in the past century.

Structural properties of the Late Pleistocene Liujiang femoral diaphyses from southern China.

The characterization of the femoral diaphysis in Pleistocene hominins with chronoecogeographical diversity plays a crucial role in evaluating evolutionary shifts in locomotor behavior and body shape. However, Pleistocene hominin fossil remains in East Asia are scarce and are widely dispersed temporally and spatially, impeding our comprehension of the nature and polarity of morphological trends. Here, we present qualitative and quantitative analyses of the cross-sectional properties and structural organization of diaphyses in two Late Pleistocene hominin femora (Liujiang PA91 and PA92) from southern China, comparing them to other Eurasian and African Pleistocene hominins.

Langebaanweg's sabertooth guild reveals an African Pliocene evolutionary hotspot for sabertooths (Carnivora; Felidae).

Here, we describe and revise craniodental material from Langebaanweg 'E' Quarry (South Africa, early Pliocene, ∼5.2 Ma), which represents one of the largest and best-preserved collections of sabertooth felids from Mio-Pliocene deposits of Africa. Four taxa, including two new species, are recognized: sp.

A computerized facial approximation method for Homo sapiens based on facial soft tissue thickness depths and geometric morphometrics.

Facial approximation (FA) provides a promising means of generating the possible facial appearance of a deceased person. It facilitates exploration of the evolutionary forces driving anatomical changes in ancestral humans and can capture public attention. Despite the recent progress made toward improving the performance of FA methods, a limited understanding of detailed quantitative craniofacial relationships between facial bone and soft tissue morphology may hinder their accuracy, and hence subjective experience and artistic interpretation are required.

Responses of soil organic carbon cycle to land degradation by isotopically tracing in a typical karst area, southwest China.

Background: The loss of soil organic carbon (SOC) under land degradation threatens crop production and reduces soil fertility and stability, which is more reflected in eco-sensitive environments. However, fewer studies simultaneously compared SOC variations and C compositions under diverse land uses, especially in karst areas.

Methods: Soil profiles from two agricultural lands and a secondary forest land were selected to analyze SOC contents and their stable isotope composition (C) in a typical karst area located in southwest China to understand the response of the SOC cycle to land degradation.

Unique Morphology of Male Inflorescence and Its Botanical Implications.

A typical angiosperm flower is usually bisexual, with entomophilous plants having four whorls of organs: the calyx, corolla, stamens, and gynoecium. The flower is usually colorful, and thus, distinct from the dull-colored reproductive organs of gymnosperms; however, this formula is not applicable to all flowers. For example, the male flower of is reduced into only a single stamen.

Hydrogeochemical characteristics and recharge sources identification based on isotopic tracing of alpine rivers in the Tibetan Plateau.

Alpine rivers originating from the Tibetan Plateau (TP) contain large amounts of water resources with high environmental sensitivity and eco-fragility. To clarify the variability and controlling factors of hydrochemistry on the headwater of the Yarlung Tsangpo River (YTR), the large river basin with the highest altitude in the world, water samples from the Chaiqu watershed were collected in 2018, and major ions, δH and δO of river water were analyzed. The values of δH (mean: -141.

Origin of adaptations to open environments and social behaviour in sabretoothed cats from the northeastern border of the Tibetan Plateau.

The iconic sabretooth is thought to have hunted cooperatively, but the origin of this behaviour and correlated morphological adaptations are largely unexplored. Here we report the most primitive species of ( sp. nov.

Seasonal climatic instability in the western Chinese Loess Plateau during Marine Isotope Stages 12-10.

Because of similar astronomical background, Marine Isotope Stage (MIS) 11 is viewed as an analogue of the Holocene, but the evolution of seasonal climatic instability during MIS 11 has not been well investigated. Here we present a time series of land-snail eggs-a recently-developed proxy of seasonal cooling events-from the Chinese Loess Plateau (CLP) to investigate seasonal climatic instability during MIS 11 and adjacent glacials. Due to the impact of low temperatures on egg hatching, egg-abundance peaks document seasonal cooling events.

Fast response of vegetation in East Asia to abrupt climatic events during the last deglaciation.

Climate changes had major impacts on the vegetation of East Asia during the last deglaciation. However, the rate and pattern of vegetation succession in response to large-scale climatic events during this interval are controversial. Here, we present well-dated decadal-resolution pollen records from annually laminated Maar Lake Xiaolongwan during the last deglaciation.